A structure of a mounting substrate of a semiconductor element, wherein a wiring conductor is partially exposed without covering with an insulating cover layer for use as a terminal has been generally known (e.g., JP-A-2001-156113).
In addition, a wiring circuit board using a polyimide layer for an insulating layer with the aim of achieving high-density mounting and high speed signal treatment of various electronic components is known. The polyimide layer is generally formed by applying a polyamide acid solution and drying the solution to form a polyamide acid layer, and heating the polyamide acid layer to allow for imidation.
The present inventors have considered covering a wiring conductor incompletely with an insulating cover layer (polyimide layer) in a wiring circuit board, thereby partially exposing the wiring conductor, and using the exposed part as a terminal.
However, a wiring circuit board having a structure wherein a part of a wiring conductor is exposed from an insulating cover layer has been found to suffer from easy occurrence of peeling of an insulating cover layer.
In view of the above situation, an object of the present invention is to provide a wiring circuit board that resists easy peeling of an insulating cover layer.